This is moving suspiciously in the direction of GD, but I’ll bite on the question of whether an employer “should” be able to fire an employee for any reason, or no reason - and the answer is an unqualified “yes.” We’re talking about creative destruction: it’s impossible to create without destroying. (An idea that’s as much Shiva as Schumpeter, really.)
Yes, that will result in dreadful unfairness to individuals. But on the whole, we have a much more dynamic labor market (and much lower unemployment) for that very reason.
The reality of human nature is that insecurity is a terrific motivator - usually the only motivator that really works. While it is true that some people will work hard regardless of how protected their positions are, anyone with experience dealing with highly unionized bureaucracies (Soviet economies, moter vehicle administrations, building trades in New York City) knows that most people will stop caring if the threat of losing their jobs disappears. (And I think most people who carefully examine their own psyches will come to the same conclusion.)
Mass layoffs can actually be beneficial if they’re strategic. IBM’s a terrific example - huge reductions as they reengineered themselves from a hardware/software company to a consulting entity. Reductions as technology changes are also rational, if painful - it simply takes many fewer works to produce a Chevy in 2003 than it did in 1973, and no amount of wishing it away will change that reality. Had GM not laid of tens of thousands, GM would no longer exist to support the remaining workers.
Of course, too often layoffs aren’t efficient - they’re just desperation. But in those cases, it’s hard to say that the employees are really harmed that much, because the employer is obviously tanking anyway. Either the employee’s fired on the way down, when at least there’s a chance for severance, or upon liquidation, when there usually aren’t enough assets left to pay it.
The best protections against this cycle are those that interfere with it least - so unemployment insurance, kept low enough so that the employee has a fire under his or her butt, is a terrific concept. I’d also like to see most benefits decoupled from employment, such as health insurance and pensions. Under our current system, these factors inhibit employees from leaving a job even when they (and the economy) might benefit - think of the secretary who has a great idea for a business, but who can’t afford to leave her kids without health coverage. So my solution is to encourage even greater labor market liquidity - not less of it.